1st Line
What is the main function of CD8+ T lymphocytes?
To recognize and destroy virus-infected, tumor, and other abnormal cells.
What is the name of the receptor that allows T lymphocytes to recognize specific antigens?
T-cell receptor (TCR)
Which type of lymphocyte produces antibodies?
B-lymphocytes.
What are cytokines?
Small signaling proteins that regulate immune responses and communication between cells.
Which type of immunity is gained through vaccination?
Artificial active immunity.
Which cells are responsible for activating naïve T lymphocytes?
Dendritic cells
What is clonal expansion of T lymphocytes?
The rapid proliferation of antigen-activated T lymphocytes, producing many cells with the same antigen specificity.
What are the two branches of adaptive immunity?
Humoral immunity and cell-mediated immunity.
Which cytokines attract immune cells to the site of infection?
Chemokines. (LC)
What is passive immunity?
Immunity gained through receiving pre-made antibodies from another source.(LC)
Which T-helper subpopulation activates macrophages and supports cellular immunity against intracellular pathogens?
Th1 cells
Which cytokine is mainly produced by Th1 cells and activates macrophages?
Interferon-gamma (IFN-γ)(LC)
What is the role of helper T cells?
They coordinate the immune response by activating B cells and other T cells.
Which cytokine stimulates the proliferation and differentiation of activated T lymphocytes?
Interleukin-2 (IL-2)
Why is active immunity generally longer lasting than passive immunity?
Active immunity produces memory cells, while passive immunity does not.
What is the immunological synapse?
A specialized contact area between a T lymphocyte and a target or antigen-presenting cell where antigen recognition and signaling occur(LC)
Explain how fever helps defend the body against infection.
It slows pathogen growth, improves immune cell activity, and promotes recovery.
How do cytotoxic T cells destroy infected cells?
They recognise antigens on MHC I and release perforins that trigger apoptosis.
What is the difference between autocrine and paracrine cytokine signaling?
Autocrine signaling acts on the cell that produces the cytokine, while paracrine signaling acts on nearby cells.
A baby receives antibodies through breast milk. What type of immunity is this?
Natural passive immunity.
What is the main difference between Th1 and Th2 cells?
Th1 cells promote cellular immunity and activate macrophages, while Th2 cells support humoral immunity by helping B cells produce antibodies.
What is the role of Fas ligand in cytotoxic T-cell activity?
Fas ligand binds to Fas receptors on target cells and activates the apoptotic pathway.
Explain why the secondary immune response is faster and stronger than the primary immune response.
Memory B and T cells remain after the first exposure and rapidly activate when the same antigen is encountered again.
What is a cytokine storm?
An excessive and uncontrolled release of cytokines that causes severe systemic inflammation and can lead to organ damage.
Compare artificial active immunity and artificial passive immunity.
Artificial active immunity uses vaccines to stimulate antibody and memory cell production, while artificial passive immunity uses injected antibodies that provide immediate protection but no memory cells.